1. Field of the Invention
The present invention relates generally to air bags. More specifically, the invention is a vehicle air bag device having a secondary air bag disposed on an adjacent wall of a primary air bag with dual inflation mechanisms, thus to provide upon deployment a cushioned or soft shell impact with a user.
2. Description of Related Art
Numerous air bag systems have been devised for providing occupant restraint within interior portions of vehicles. Most air bag systems are housed in the steering column on the driver's side, and in a separate compartment within the dashboard on the passenger side. The primary modification to the conventional dual air bag system has been directed to minimizing injuries to passengers during the initial phase of deployment of the air bag, under near rip seam pressures. However, there has yet to be provided an air bag system which utilizes a soft shell pressure differential as a remedy to the problem.
For example, U.S. Pat. No. 3,907,327 issued to Pech discloses a safety device with an inflatable cushion which provides effective protection during successive collisions. The device comprises a detector which controls the actuation of pressurized gas for inflating the safety cushion. The cushion has two walls made of flexible material, which are of substantially the same dimensions, located one inside the other. The cushion expands in a conventional manner via pressurized gas and takes up a position between a person or passenger to be protected and the rigid structures of a vehicle. The interior walls of the inflatable cushion are connected as discontinuous elements which form non-communicating chambers.
Non-communicating inflatable chambers have been widely used in conventional air bag systems. U.S. Patents issued to Melvin et al. (U.S. Pat. No. 5,282,646), Shiota et al. (U.S. Pat. No. 5,427,410), Gille (U.S. Pat. No. 5,435,594 and U.S. Pat. No. 5,468,013) disclose multi-chamber or dual chamber systems as non-communicating chambers. The general arrangement includes an inflatable chamber disposed within another inflatable chamber which deploys upon a sensed crash event. A single pressurized gas channel is used to inflate each non-communicating chamber simultaneously.
U.S. Pat. No. 5,282,646 issued to Melvin et al. discloses a multi-chamber air bag having a displacement responsive valve. The air bag also has an internal dividing wall which divides the air bag into a first chamber communicating directly with the inflator and a second chamber defined between the dividing wall and the occupant-contacting face wall. A first opening in the dividing wall between the chambers communicate inflation gas from the first chamber to the second chamber to inflate the second chamber. A second opening in the dividing wall is normally closed by a vent flap or tethered flap which is operably connected to the occupant-contacting face wall so that the inflation of the second chamber and resultant travel of the face wall toward the occupant and away from the dividing wall will move the valve flap to an open position to further inflate the air bag.
Other conventional air bag systems include canisters which have dual stage inflators. Among these are U.S. Patents issued to Patel et al. (U.S. Pat. No. 5,513,879), Marchant (U.S. Pat. No. 5,564,743), Wolanin (U.S. Pat. No. 5,762,367) and Taguchi et al. (U.S. Pat. No. 5,951,038). These devices work on the general principle wherein a two stage inflator provides a gentle onset of inflation during the initial employment to help protect out-of-position passengers. A second rapid stage is ignited passively by hot gas communication from the first stage. The inflation gases from both stages flow through a module funnel into the air bag. Multiple air bag arrangements for the head, torso and knees are disclosed in the U.S. Pat. No. 5,775,729 issued to Schneider et al.
Foreign Patents granted to Hirokazu (EPO 0399498) and Iritani (GB 2265118) disclose similar air bag constructions which are of general relevance to the soft shell air bag system. The air bag system taught by Iritani discloses an inner and outer chamber system with the wall of the inner chamber having a plurality of apertures for supplying gas to the second or outer chamber.
None of the above inventions and patents, taken either singly or in combination, is seen to describe the instant invention as claimed.